This invention relates, generally, to the field of spindle mounted bearings and, more particularly, to an adjustable spacer placed between such bearings mounted on a spindle or the like, as well as a system for adjusting such an adjustable spacer.
Anti-friction bearings serve to decrease friction of and provide support for, for example, a hub upon which a wheel is mounted, for instance, to rotate about a spindle. Such bearings may comprise roller bearings, for example, tapered roller bearings. The spindle may comprise, for instance, an axle or a shaft.
A typical tapered roller bearing includes a cone having an inner race for mounting on a spindle, a cup having an outer race for mounting in a hub, and a plurality of roller elements within a roller cage positioned between the inner and outer races. Commonly, a pair of such tapered roller bearings are mounted on a spindle for rotation thereabout of a wheel mounted on a hub. Cooperating bearings, such as a pair of tapered roller bearings, may be included in a bearing assembly.
In order to properly secure bearings in many axle, spindle, and transmission assemblies, it is necessary to retain the bearings tightly under a predetermined axial load on the shaft or axle, so that they will maintain the proper running clearance of the roller elements under the influence of the combined axial and radial forces which they are designed to support. It is often the practice of manufacturers of such assemblies to carefully measure the space between the bearing inner races, and provide a spacer of precisely the correct dimension and load requirements to fit therebetween. The spacer is often made of ground steel tubing to a length tolerance of plus or minus one half of one thousandth of an inch. If the bearings are not maintained at a proper load the bearings may not roll properly or may prematurely wear, particularly if the bearings are maintained at too high of a load, or may, if maintained under too low of a load, have excessive play causing failure of the bearings and wheel supported thereon.
Certain assemblies employ an adjustable spacer or load ring which can be fitted by means of loading within the assembly. In assemblies which are subject to high loading during service, it may be required that the spacer have a very high capacity to resist being deformed. In one example, an adapter sleeve optionally may be employed in conjunction with the spacer between a pair of roller bearings, such as for accommodation of differing spindle dimensions at each bearing location.
An exemplary embodiment of such an adapter sleeve and adjustable spacer is disclosed in commonly owned U.S. Pat. No. 5,549,397 to Rode (entitled xe2x80x9cAdapter Sleeve and an Adjustable Spacer With Radial Extension Useable Thereonxe2x80x9d and issued Aug. 27, 1996) and in commonly owned U.S. application Ser. No. 08/661,349 of Rode (entitled xe2x80x9cAdjustable Bearing Assembly and Adapter Sleeve Thereforxe2x80x9d and filed Jun. 14, 1996), which are hereby incorporated herein by reference in their entireties.
One approach to preparing a bearing assembly with an adjustable spacer which is subject to high-shock loading, requires sensing of the resistance to rolling torque that is encountered when a tapered roller bearing is loaded axially. The sensed resistance is used as an indicator of whether the bearings are correctly positioned.
However, some assemblies do not permit such an approach, such as where the bearing is pre-assembled as a cone and cup assembly with a lubrication seal. In particular, the seal, when new, can cause a significant resistance to rolling torque, thereby interfering with the ability to sense the rolling drag of a lightly-preloaded bearing.
In other designs, it may be preferable to use a method of adjusting the spacer without relying upon torque resistance measurement. Unfortunately, such a method can undesirably require the making of dimensional measurements, which are desirable to avoid since they are time-consuming and allow errors to be introduced by the assembler.
Thus, a need exists for improving performance, easing use, and increasing adjustability of an adjustable spacer employed with a bearing assembly. A further need exists for improving ease, accuracy, and control of adjustment to an adjustable spacer employed with a bearing assembly. A need also exists for decreasing dimensional measurements required to properly prepare a spacer and bearing assembly. An additional need exists for decreasing the number of parts, and attendant positioning complexity, required to satisfy a function provided by an adapter sleeve and an adjustable spacer employed with a bearing assembly.
Pursuant to the present invention, shortcomings of the existing art are overcome and additional advantages are provided through the provision of a bearing assembly adjustable spacer and a system for adjusting the same. In one aspect of the invention, a spacer-adjustment system includes a high-compression section and a low-compression section. The high-compression section is adapted to receive a spacer for a bearing assembly. The low-compression section is adapted to receive the bearing assembly. Also, a selected limit of travel during compression of the bearing assembly with the low-compression section, serves to provide a desired adjustment to the spacer with the high-compression section.
In another aspect of the invention, the desired adjustment can comprise a preload. The bearing assembly can include a bearing housing, a hub, a first bearing, a second bearing and/or a displacement gage. Also, the displacement gage can be adapted to separate the first and second bearings by a gaged distance. The low-compression section can serve to substantially replicate a selected spindle for mounting of the bearing assembly.
The high-compression section can include a hydraulic cylinder, an electrohydraulic mechanism, and/or a lead screw device for providing the desired adjustment to the spacer. A sensor can signal the hydraulic cylinder and/or the electrohydraulic mechanism to halt compression for accomplishment of the desired adjustment. A sensor can activate a brake for the lead screw device to accomplish the desired adjustment.
The selected limit of travel can be signalled by a sensor. The sensor can comprise a pressure switch. The sensor can be adapted to be adjusted to account for a deflection of the sensor upon a contact thereof.
The high-compression section can be connected with the low-compression section for transfer therebetween of a dimension of space remaining in the bearing assembly for the spacer. The dimension of space can be employed in providing the desired adjustment to the spacer.
A transfer frame, an air cylinder, and/or a tie bar can serve to connect the high-compression section with the low-compression section. The high-compression section can be adapted to exert a high force on the spacer. Also, the low-compression section can be adapted to exert a low force on the bearing assembly. Further, the high force and the low force can have a scaled relationship.
The low-compression section can include a mechanism for assuring the desired adjustment allows proper seating of at least one component of the bearing assembly. The mechanism can comprise a device for rotating at least the at least one component of the bearing assembly.
In yet another aspect of the present invention, a spacer-adjustment system includes a high-compression section and a low-compression section. The high-compression section is adapted to receive a spacer for a bearing assembly. The low-compression section is adapted to receive the bearing assembly. A transfer frame serves as a mechanical interface between the high-compression section and the low-compression section. Also, the transfer frame is adapted to transfer to the low-compression section a first travel indicative of a first compression of the spacer with the high-compression section. A sensor is coupled with the high-compression section and the low-compression section. Further, the sensor serves to limit the first compression according to a second travel indicative of a second compression of the bearing assembly with the low-compression section. Additionally, the first travel and the second travel are related to provide a desired adjustment to the spacer.
The invention further contemplates a method for deforming a spacer useable for separating bearings mounted on a spindle. The spacer is placed in a variable length adjustment chamber of a high-compression section. The bearings are positioned in a low-compression section. Also, the positioning of the bearings serves to resemble an arrangement of the bearings separated by the spacer on the spindle. The length adjustment chamber is decreased to exert a first compressive force on the spacer. A second compressive force is applied on the bearings according to a selected relationship between the spacer and at least one of the bearings and/or the spindle. There is sensed a result in the low-compression section of the second compressive force. The result is employed to limit the decreasing of the variable length adjustment chamber, and provide the spacer with a desired adjustment.
In a further aspect of the invention, the selected relationship between the spacer and at least one of the bearings and/or the spindle can be configured for transfer between the high-compression section and the low-compression section of a dimension of space between the bearings, for the spacer. At least one component of the bearings can be rotated to assure proper seating thereof.
Thus, the present invention advantageously provides improved performance, easier use, and increased adjustability of an adjustable spacer employed with a bearing assembly. Further, the invention improves ease, accuracy, and control of adjustment to an adjustable spacer employed with a bearing assembly. Also, the present invention decreases requirements for dimensional measurements to properly prepare a spacer and bearing assembly. Additionally, the invention decreases the number of parts, and attendant positioning complexity, required to satisfy a function provided by an adapter sleeve and an adjustable spacer employed with a bearing assembly.